Instructions
Collect 50 rupees by defeating enemies and cutting grass around Hyrule. Once you have 50, head to the Bomb Shop in West Clock Town.
Put on the Goron Mask before you head inside. Talk to the shopkeeper and purchase a powder keg with your 50 rupees.
Go to Milk Road and put the keg by the boulder that blocks the path to the ranch. Blow up the keg to clear the road.
Take off your mask before you enter the ranch. Go right at the fork and talk to Tatl and then Romani. They will let you practice target shooting while riding Epona.
Hit all 10 of the dummies with your bow and arrow in less than two minutes while riding the horse. If you are successful you will get Epona for use in the quest, and will learn a song for your ocarina that will call her when you are separated.